Endoscopic vision system

ABSTRACT

The present invention relates to an endoscopic visioning system and related method for both forward and backward viewing of a body lumen. According to an embodiment, the system includes an endoscope, a vision head including a light source and a vision chip on both a proximal and a distal side of the vision head, and an extension arm for moving the vision head away from and back toward the endoscope. Alternatively, the light source and vision chip may be contained in a distal end of the endoscope. In -such an alternative embodiment, the vision head is a parabolic mirror mounted on the extension arm for reflecting images, for example, from behind the distal end of the endoscope to the vision chip in the distal end of the endoscope to permit, for example, a retrograde view of the surgical site entrance.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an endoscopic vision system and arelated method of viewing a body lumen.

2. Background of the Related Art

Millions of endoluminal procedures are performed each year. Anendoluminal procedure takes place within a tube, or lumen, of the humanbody, such as a vascular, gastrointestinal, or air exchange lumen, andgenerally involves the diagnosis and/or treatment of diseases.Endoluminal procedures generally involve use of an endoscope, a rigid orflexible tube which can be introduced into the human body through theentrance to a lumen of the body, such as the mouth or rectum.Alternatively, an endoscope may be inserted into the human body throughan incision made by a surgeon. The endoscope allows the surgeon to viewthe patient and an intended surgical site internally without the surgeonbeing in a direct line of sight with the object or area being viewed.The endoscope provides one or more open, working channels, or pathways,between a desired surgical site and the surgeon. An endoscope may carry,for example, one or more lights, visioning systems, and other tools,such as diagnostic and treatment devices that extend from a proximal endnear by the surgeon, through the working channel, and to the distal endat a surgical site. The size of the endoscope used may vary, dependingon the particular lumen of the patient and the size and number ofinstruments which need to be introduced to the surgical site.

Endoscopes typically are manually inserted into the patient by thesurgeon and manually steered or positioned by the surgeon or nurse bypushing the endoscope through the body until the endoscope is properlypositioned. Dependent upon the size and flexibility of the endoscopeused, forcing the endoscope into a lumen of the patient may traumatizethe surrounding tissues. Thus, the ability to visualize the area intowhich the endoscope is being inserted is important. To view the area, anendoscope may communicate with a monitor to display the field of view.However, lack of an adequate field of vision, poor resolution, and poorillumination are problems in existing endoscopic visioning systems whichmake it difficult for a surgeon to view the surgical area and accuratelyposition an endoscope.

FIGS. 1 and 2 illustrate an embodiment of a conventional endoscope. Itincludes an insertion tube, a lumen or working channel within theinsertion tube, a light source and a vision chip. Such an endoscope hasseveral limitations. For example, the opening to the working channel,the light source, and the vision chip are each restricted to, forexample, a couple of millimeters in diameter. This compromisesperformance of the visioning system and increases costs for componentsof the system due to the need to miniaturize the components. The limitedspace available on a working end of a conventional endoscope restrictsthe size of the visioning system. Such visioning elements also take awayneeded space for the working channel(s) of the endoscope-limiting thesize and number of the tools which can pass through the working channel.

Larger, more rigid endoscopes can support larger, more powerful lightsources for better illumination and larger vision chips for betterresolution. Such endoscopes, however, lack flexibility, making it moredifficult to maneuver the endoscope within the body. Smaller,articulating endoscopes are much more flexible but are relatively smallin diameter, and thus lack the size necessary to support largerillumination and resolution elements.

In addition, such a system is only forward-looking, and has a relativelynarrow field of vision, with a viewing angle of, for example, about 120degrees, as shown in FIG. 2. This makes it extremely difficult for asurgeon to view the region where the endoscope enters the body lumen.Very flexible endoscopes may perform what is known as a“scope-retrograde” maneuver, in which the endoscope bends back uponitself to allow the user to visualize the endoscope's point of entry.Such endoscopes are expensive, require expertise on the part of theoperator, and require space within the body lumen to perform such amaneuver.

In light of the difficulty in positioning devices introduced into thehuman body through endoscopes, the difficulty in maximizing workingchannel space, and the difficulty of providing adequate illumination,resolution, and field of vision in existing visioning systems forendoscopes, there is a need for a method and device which solve theseproblems.

SUMMARY OF THE INVENTION

In light of the drawbacks of the visioning systems described, there is aneed for an endoscopic visioning system capable of providing an adequatefield of vision, improved illumination and resolution, and increasedworking channel space. Accordingly, the present invention is directed toan improved device that obviates the limitations and disadvantages ofconventional endoscopic visioning systems.

To achieve these and other advantages and in accordance with the presentinvention, as embodied and broadly described herein, an endoscopicdevice is provided. The endoscopic device includes an endoscope havingproximal and distal ends, an extension arm passing through a channel inthe endoscope to the distal end of the endoscope, and a head attached toa distal end of the extension arm wherein the head includes a visionmember capable of receiving an image of a surgical site.

According to another aspect of the invention, the endoscopic deviceincludes an endoscope having proximal and distal ends, an extension armpassing through a channel in the endoscope to the distal end of theendoscope, and a mirror attached to a distal end of the extension arm.

According to a further aspect of the invention, a method for viewing asurgical site in a body lumen is provided. The method includes placing adistal end of an endoscope into a body lumen, extending an extension armto move a distal end of the extension arm away from a distal end of theendoscope, and viewing the surgical site with a vision member attachedto the distal end of the extension arm, the surgical site being proximalto the vision member.

Additional features and advantages of the present invention will be setforth in the description which follows, and in part will be apparentfrom the description, or may be learned by practice of the invention.The objectives and advantages of the invention will be realized andattained by means of the elements and combinations particularly pointedout in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate various embodiments of theinvention and together with the description, serve to explain theprinciples of the invention. In the drawings,

FIG. 1 is an isometric side view of an endoscope with a conventionalvisioning system;

FIG. 2 is an isometric side view the endoscope of FIG. 1 displaying thefield of vision for conventional endoscopic visioning systems;

FIG. 3 is an isometric side view of an endoscope with a visioning systemaccording to a first embodiment of the present invention;

FIG. 4 is an isometric side view of the endoscope of FIG. 3 with avision head in an extended position;

FIG. 5 is an isometric side view of the endoscope of FIG. 3 with avision head in an angled position;

FIG. 6 is an isometric side view of an endoscope with a visioning systemaccording to a second embodiment of the present invention;

FIG. 7 is an isometric side view of the endoscope of FIG. 6 showing thefield of vision for the visioning system of the endoscope of FIG. 6; and

FIG. 8 is a flow chart showing the process used to correct distortion inthe visioning system of the endoscope of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

According to the present invention, an endoscopic visioning system isprovided. A first embodiment of the endoscopic visioning system includesan endoscope, an extension arm, and a vision head attached to theextension arm. The vision head is extensible within a body lumen awayfrom and back toward the endoscope. The vision head is also rotatableand capable of being angled with respect to a longitudinal axis of theendoscope. The vision head preferably includes at least one vision chipand light source, and more preferably may include a vision chip andlight source on both a proximal and a distal face of the vision head.

A second embodiment of the endoscopic visioning system includes anendoscope, an extension arm, and a mirror attached to the extension arm.The mirror is preferably a parabolic mirror. The mirror is extensiblewithin a body lumen away from and back toward the endoscope. The mirroris also rotatable and capable of being angled with respect to alongitudinal axis of the endoscope. A distal end of the endoscopeincludes a vision chip and a light source. The reflective surface of themirror faces the distal end of the endoscope such that an image of anarea more toward the proximal end of the endoscope may reflect off ofthe mirror to the vision chip. The vision system preferably alsoincludes distortion correction means for correcting distortion of theimage due to the mirror. Preferably, the distortion correction meansincludes a digitizer in communication with appropriate computersoftware.

The use of an extensible vision head or mirror allows for better viewingas an endoscope enters the body and during further insertion of theendoscope into the body lumen. This allows for easier and more accuratepositioning of the endoscope within the body. The improved accuracyreduces the amount of time needed for the surgery/treatment and reducesthe risk of erroneously cutting/treating the wrong tissue. The abilityto extend, rotate, and angle the vision head or mirror maximizes thefield of vision of the user.

In addition, by separating the vision elements, such as the vision chipand light source, from the distal end of the endoscope, more spacebecomes available on the distal end and within the endoscope itself,i.e., there is no longer a need to provide space on the distal end ofthe endoscope for the vision chip and the light source. Thus, it ispossible that the endoscope may have more than one lumen or a largerlumen (working channel) available to pass/contain tools for thesurgery/treatment.

In addition, a mirror or a second set of vision elements on a proximalside of the vision head provides a surgeon with a view of the entry siteof the endoscope within the body lumen or a view of other areas near theproximal end of the endoscope. There is no need for space within thebody lumen to maneuver the endoscope back on itself to view the entrypoint, nor is there a need for an extremely flexible endoscope whichcannot support the visioning system. In addition, this means thatrequirements for tools used within the endoscope will be lessrestrictive.

According to a first preferred embodiment of the present invention andas shown in FIG. 3, an endoscopic visioning system 100 is provided.System 100 generally may include an endoscope, an extension arm, and avision head. Each of these general portions of system 100 will bedescribed in detail.

As embodied herein and shown in FIGS. 3-5, an endoscope 110 is provided.Endoscope 110 may be of any suitable diameter so as to be capable ofinsertion into a body lumen and to contain the necessary tools for aparticular procedure to be performed in the body lumen. Endoscope 110has a proximal end (not shown) and a distal end 114, wherein the distalend 114 is the end of endoscope 110 inserted into a body lumen.Endoscope 110 may be either a disposable endoscope or a reusableendoscope. If endoscope 110 is a reusable endoscope, it should be madefrom materials easily cleanable and sterilizable. If endoscope 110 isdisposable, it may be made from any suitable biocompatible material,such as a plastic or other polymer. The exterior of endoscope 110 mayhave a hydrophilic coating to facilitate its passage through the bodylumen. Endoscope 110 also includes at least one lumen or working channel116 a, 116 b, 116 c for receiving surgical instruments. Preferablyendoscope 110 includes more than one lumen for receiving the surgicalinstruments. Endoscope 110 also includes a lumen 118 configured toreceive an extension arm 120.

As embodied herein and shown in FIG. 3, endoscopic visioning system 100also includes a vision head 130. Vision head 130 includes a proximalface 132 and a distal face 134. Vision head 130 is mounted on anextension arm 120 which passes through lumen 118 of endoscope 110.Vision head 130 is preferably mounted to extension arm 120 by a balljoint 122 but may be mounted by any other mechanical connectionpermitting articulating motion relative to extension arm 120. Ball joint122 allows the vision head 130 to be angled with respect to alongitudinal axis of the endoscope 110. In addition, vision head 130 isrotatable about its longitudinal axis by rotation of the extension arm120 within its lumen 118. Movement of the vision head 130 throughextension arm 120 is preferably controlled from the proximal end of theendoscope 110 through any suitable actuator known in the art. Visionhead 130 is moveable away from and back toward the distal end 114 ofendoscope 110 on extension arm 120. When the vision head 130 is locatednext to the distal end 114 of endoscope 110, the proximal face 132 ofvision head 130 is adjacent the distal end 114 of the endoscope 110. Ina preferred embodiment, vision head 130 has a diameter approximately thesame as a diameter of the endoscope 110. The vision head diameter,however, may be smaller or larger than that of the distal end of theendoscope should the need arise. Also in a preferred embodiment, thelumen for extension arm 120 is located towards the periphery of thedistal end of the endoscope. The extension arm lumen, however, may bepositioned at any other suitable location should it, for example, bedesirable to locate all surgical instrument lumens along the peripheryof the distal end of the endoscope. The extension arm 120 may be made ofstainless steel, plastic, or other suitable materials, and the visionhead 130 may be made of the same or similar materials as the endoscope.The extension arm 120 is preferably a rod or rigid tube, but may be inany other suitable form.

The distal face 134 of vision head 130 includes a distal light source140 and a distal vision chip 150. Preferably, the proximal face 132 ofvision head 130 also includes a proximal light source 142 and a proximalvision chip 152. The distal light source 140 and distal vision chip 150allow for forward-looking vision within the body lumen. The proximallight source 142 and proximal vision chip 152 allow backward-looking(toward the entry site of the endoscope into the body lumen) vision orretrograde vision. Retrograde vision is only possible when the visionhead 130 is extended away from the distal end 114 of the endoscope 110.Preferably, only one set of vision elements, forward-looking orbackward-looking, is active at one time, which also may be controlledthrough appropriate structure at the proximal end of the endoscope.

Light sources 140, 142 are used to illuminate an area of which an imageis to be taken. Vision chips 150, 152 obtain image information and passvideo image data via electrical leads contained within the extension arm120 to appropriate circuitry that will digitize the video data andcommunicate that data to a computer having suitable software to formatthe data and cause it to be displayed on a video display system locatedexternal to the endoscope. Extension arm 120 also contains electricalleads connected to an external power supply to supply power to theelectronics contained in the vision head 130. Because all of the visionelectronics are contained in the vision head 130, there is no need tohave separate lumens leading to a light source and a vision chip. Thisresults in additional space which can be used to pass surgicalinstruments to the surgical site.

In use, the distal face 134 of the vision head 130 is used to receiveimage information in front of (i.e., distal to) the endoscope 110. Thedistal face 134 may be extended (i.e., moved further away from thedistal end 114 of the endoscope 110) in order to allow the user to get acloser view of an area of interest. Additionally, the distal face 134may be extended, rotated, and angled by the user in a search for theoptimal path for advancement of the entire endoscope further into thebody cavity toward a desired surgical/treatment site, or to more closelyview a surgical site, for example. Such manipulation of the vision head130 maximizes the field of vision. The vision head 130 need not beextended, however, for the vision chip 150 to receive forward-lookingimage information.

To receive backward-looking or retrograde image data, the distal face134 must be extended such that there is a space between the distal end114 of the endoscope 110 and the proximal face 132 of the vision head130. The further away the proximal face 132 of the vision head 130 isfrom the distal end 114 of the endoscope 110, the broader the view theproximal vision chip 152 will be able to image. In addition, theproximal face 132 may be extended, rotated, and angled, as controlled bya user from the proximal end of the endoscope 110, in order to obtainthe clearest view of the point of entry of the endoscope into the bodylumen. Such manipulation of the vision head 130 maximizes the field ofvision.

In each case, forward-looking viewing or backward-looking viewing, thevision chip receives the image data. The vision chip passes image data,via leads in extension arm 120, to appropriate digitizing circuitry,appropriate computer software, and ultimately to a video display locatedexternal to the endoscope 110. The image is then viewed by the user onthe display so that the user may further manipulate the endoscope and/orthe endoscopic instruments therein for accurate positioning andtreatment. Further manipulation of the position of the vision head willresult in manipulation of the image viewed on the display.

According to a second preferred embodiment of the present invention andas shown in FIG. 6, an endoscopic visioning system 200 is provided.System 200 generally may include an endoscope, an extension arm, and amirror. Each of these general portions of system 200 will be describedin detail.

As embodied herein and shown in FIGS. 6 and 7, an endoscope 210 isprovided. Endoscope 210 may be of any suitable diameter so as to becapable of insertion into a body lumen and to contain the necessarytools for a particular procedure to be performed in the body lumen.Endoscope 210 has a proximal end (not shown) and a distal end 214,wherein distal end 214 is the end of endoscope 210 inserted into a bodylumen. Endoscope 210 may be either a disposable endoscope or a reusableendoscope. The exterior of endoscope 210 may have a hydrophilic coatingto facilitate its passage through the body lumen. Endoscope 210 alsoincludes at least one lumen or working channel 216 for receiving forreceiving surgical instruments. Endoscope 210 also includes a lumen 218configured to receive an extension arm 220, lumen 219 a configured toreceive appropriate elements for connection to a light source 240, andlumen 219 b configured to receive appropriate elements for connection toa vision chip 250 at the distal end 214.

As embodied herein and shown in FIGS. 6 and 7, endoscopic visioningsystem 200 also includes a mirror 230. Mirror 230 is preferably aparabolic mirror. Mirror 230 includes a proximal parabolic reflectiveface 232. Mirror 230 is mounted on an extension arm 220 which passesthrough lumen 218 of endoscope 210. Mirror 230 is preferably mounted toextension arm 220 by a ball joint 222 but may be mounted by any othersuitable mechanical connection to extension arm 220. If a flat mirror isused instead of a parabolic mirror, ball joint 222 may allow the mirrorto be angled with respect to a longitudinal axis of the endoscope 210.Preferably, parabolic mirror 230 is not rotatable about its longitudinalaxis by rotation of the extension arm 220. Alternatively, if a flatmirror is used instead of a parabolic mirror, it may be desirable toprovide rotation of the mirror about its longitudinal axis. In addition,rotation of the mirror may allow movement of the mirror out of the lineof sight of a vision chip 250 which is carried in the distal end 214 ofthe endoscope 210. Movement of either a parabolic mirror or a flatmirror out of the line of sight of the vision chip 250 will permitgathering of forward-looking image data.

Movement of the mirror 230 through extension arm 220 is preferablycontrolled from the proximal end of the endoscope 210 through anysuitable actuator known in the art. Mirror 230 is moveable away from andback toward the distal end 214 of endoscope 210 on extension arm 220.When the mirror 230 is located next to the distal end 214 of endoscope210, the parabolic reflective face 232 of mirror 230 is adjacent thedistal end 214 of the endoscope 210. In a preferred embodiment,parabolic mirror 230 has a diameter approximately the same as a diameterof the endoscope 210. The mirror diameter, however, may be smaller orlarger than that of the distal end of the endoscope should the needarise. Also in a preferred embodiment, the lumen for extension arm 220is located towards the periphery of the distal end of the endoscope. Theextension arm lumen, however, may be positioned at any other suitablelocation should it, for example, be desirable to locate all surgicalinstrument lumens along the periphery of the distal end of theendoscope. The extension arm 220 may be made of stainless steel,plastic, or other suitable materials, and the mirror 230 may be made ofany suitable reflective materials. The extension arm 220 is preferably arod or rigid tube, but may be in any other suitable form.

The distal face 214 of endoscope 210 includes the light source 240 andthe vision chip 250. The light source 240 and vision chip 250, when usedwithout mirror 230, allow for forward-looking vision within the bodylumen. The light source 240 and vision chip 250, when used inconjunction with mirror 230, allow backward-looking (toward the entrysite of the endoscope) vision or retrograde vision as shown in FIG. 7.Retrograde vision is possible when the mirror 230 is extended away fromthe distal end 214 of the endoscope 210 and is substantially aligned(i.e., is concentric with endoscope 210) to reflect an image back tovision chip 250. If mirror 230 is rotated to become unaligned with thedistal end 214 of endoscope 210, it is possible for vision chip 250 toreceive forward-looking image data and pass such data to appropriateelectronic circuitry and software and preferably to a video displaylocated external to the endoscope 210 through appropriate interfaces.When mirror 230 is aligned with vision chip 250, a retrograde orbackward-looking image is reflected off of the reflective surface 232 ofmirror 230 to vision chip 250. The received image data is then sent fromvision chip 250 to be displayed.

The parabolic mirror, in use, provides a viewing angle of nearly 180degrees facing the entry point (i.e., towards the proximal end) of theendoscope 210 within the body lumen (see FIG. 7). Use of the parabolicmirror, while providing a very wide viewing angle, also introduces alarge amount of spherical distortion of the video image. The currentinvention corrects for this distortion by digitizing the image data andusing appropriate computer software to correct the image to anorthographic format. The process for correcting for the distortion isshown in the flowchart of FIG. 8. The vision chip 250 collects videoimages reflected from the reflective surface 232 of mirror 230 andrelays the analog video data to a video circuit board, preferably withina computer. The analog data is then converted to digital data. Next, thedigitized data is operated on by a computer program run on the computerto remove the spherical distortion. An example of a program which canperform this function is OMNIVIDEO, written by researchers at ColumbiaUniversity, and available at the websitewww.cs.columbia.edu/CAVE/omnicam/. This software is exemplary only, andother suitable software may be developed for use with this invention.

Once the image has been made distortion free, it is displayed on thevideo display connected to the computer. The software provides the userwith a distortion free image within the overall field of view from themirror. That view can be changed in magnification and direction inreal-time, without changing the position of the endoscope 210, viacommands issued to the system through a suitable program user interfaceknown to persons skilled in the art. In addition, the breadth of theview can be increased or decreased by extending or retracting,respectively, the mirror 230 with respect to the distal end 214 of theendoscope 210.

Alternatively, as discussed above, if a flat mirror is used instead of aparabolic mirror, the mirror may be angled with respect to the extensionarm 220 to obtain a different view. Further, rotation of a flat mirrorabout its longitudinal axis may also provide a different view. As withthe parabolic mirror, the breadth and detail of the view can beincreased or decreased by extending or retracting, respectively, themirror 230 with respect to the distal end 214 of the endoscope 210.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the system of the presentinvention and in construction of the system without departing from thescope or spirit of the invention. Other embodiments of the inventionwill be apparent to those skilled in the art from consideration of thespecification and practice of the invention disclosed herein. It isintended that the specification and examples be considered as exemplaryonly.

1-44. (canceled)
 45. An endoscopic system, comprising: an endoscopeincluding at least two lumens and having a proximal and a distal end; anextension arm passing through one of the lumens to the distal end of theendoscope; and a vision head connected to a distal end of the extensionarm, a distal face of the vision head including a distal vision chip andbeing configured to obtain a forward-looking image when the head isadjacent to the distal end of the endoscope, and a proximal face of thevision head including a proximal vision chip and being configured toobtain a backward-looking image when the vision head is spaced away fromthe distal end of the endoscope.
 46. The endoscopic system of claim 45,further comprising an actuator for controlling movement of the extensionarm and the vision head.
 47. The endoscopic system of claim 46, whereinthe actuator is configured to control extension, retraction, androtation of the arm and vision head.
 48. The endoscopic system of claim45, wherein the vision head is connected to the extension arm in amanner that permits articulation of the vision head relative to theextension arm, and further comprising an angular control for controllingarticulation of the vision head with respect to the extension arm. 49.The endoscopic system of claim 48, wherein the arm is connected to thevision head by a ball joint.
 50. An endoscopic system, comprising: anendoscope including at least two lumens and having a proximal and adistal end, the distal end of the endoscope having a vision chip; anextension arm passing through one of the lumens of the distal end of theendoscope; and a mirror connected to a distal end of the extension arm,the mirror being extendable, rotatable, and angled relative to theextension arm to provide a maximum field of vision.
 51. The endoscopicsystem of claim 50, wherein the mirror is moveable toward and away fromthe distal end of the endoscope on the extension arm.
 52. The endoscopicsystem of claim 50, wherein the mirror is a parabolic mirror.
 53. Theendoscopic system of claim 52, wherein a parabolic surface of the mirrorfaces the distal end of the endoscope.
 54. The endoscopic system ofclaim 50, wherein the vision chip is positioned to obtain an imagereflected in a mirrored surface of the mirror.
 55. The endoscopic systemof claim 54, further comprising distortion correction means forcorrecting distortion of the image due to the mirror.
 56. A method ofproviding retrograde vision with an endoscopic system, comprising:providing an endoscopic system comprising an endoscope, a distal end ofthe endoscope having a vision chip, an extension arm passing through alumen of the endoscope to the distal end of the endoscope, and a mirrorconnected to a distal end of the extension arm; placing the mirror andthe distal end of the endoscope into a body lumen; extending the mirroraway from the distal end of the endoscope; retrograde viewing an imagewith the mirror; obtaining the retrograde image reflected in the mirrorwith the vision chip; and correcting distortion of the image caused bythe mirror.
 57. The method of claim 56, further comprising transmittingthe image to a video display.
 58. The method of claim 56, whereinextending the mirror away from the distal end of the endoscope includesmoving the mirror with the extension arm.
 59. The method of claim 56,wherein providing the mirror connected to the distal end of theextension arm includes providing a parabolic mirror.
 60. The method ofclaim 59, wherein providing the parabolic mirror includes providing themirror such that a parabolic surface of the mirror faces the distal endof the endoscope.
 61. A method for obtaining images of a surgical sitewith an endoscopic system, comprising: providing an endoscopic systemcomprising an endoscope, a vision head having proximal and distal faces,each face including a vision chip, and an extension arm passing througha lumen of the endoscope to a distal end of the endoscope, a distal endof the extension arm being connected to the vision head; placing thevision head and the distal end of the endoscope into a body lumen;forwardly viewing an image with the vision chip in the distal face ofthe vision head while the vision head is adjacent to the distal end ofthe endoscope; extending the vision head away from the distal end of theendoscope; and retrogradely viewing an image with the vision chip in theproximal face of the vision head while the vision head is spaced awayfrom the distal end of the endoscope.
 62. The method of claim 61,further comprising controlling movement of the extension arm and thevision head with an actuator at the proximal end of the endoscope. 63.The method of claim 62, wherein controlling movement includes extendingthe arm, retracting the arm, and rotating the vision head.
 64. Themethod of claim 61, further comprising controlling articulation of thevision head relative to the extension arm to provide a maximum field ofview.